CdSe quantum dots (QDs) hybridized with graphene oxide (GO) are synthesized by a facile chemical precipitation method. The absorption of the CdSe/GO nanocomposite is increased with a significant blue shift with respect to CdSe QDs. The specific surface area of the CdSe/GO nanocomposite is 10.4 m2/g, which is higher than that of CdSe QDs (5 m2/g). The PL intensity of the CdSe/GO nanocompo-site is lower than that of the CdSe QDs owing to the inhibition of the recombination of electron-hole pairs in the composite. In Raman analysis, the two bands of the CdSe/GO nanocomposite are shifted to higher wavenumbers with respect to graphene oxide, which is attributed to electron injection that is induced by CdSe QDs into graphene oxide. Using the Brilliant Green dye, the photocatalytic reduction efficiency of CdSe QDs and the CdSe/GO nanocomposite under sunlight irradiation for 90 min are approximately 81.9% and 95.5%, respectively. The calculated photodegradation rate con-stants for CdSe QDs and the CdSe/GO nanocomposite are 0.0190 min–1 and 0.0345 min–1, respec-tively. The enhanced photocatalytic activity of the CdSe/GO nanocomposite can be attributed to the high specific surface area and the reduction of electron-hole pair recombination because of the introduction of graphene oxide.%纺织、塑料、造纸和纸浆等工业排放物中含有大量的有机染料,这些染料通常不可生物降解,从而产生了严重的环境污染问题.为了降解这些有机染料废弃物,人们迫切需要高效、廉价、稳定的有机物降解光催化剂.近年来,半导体光催化剂引起了人们的广泛关注,尤其是窄禁带半导体材料可以实现染料的高效降解.在半导体II-VI族中,CdSe具有合适的带隙(1.74 eV)和快速生成的电子-空穴对,被认为是光催化降解有机污染物的重要半导体材料.特别是当它与超高的电子导电性的碳基纳米材料结合时,光催化活性增强.本文采用一种简单的化学沉淀法成功合成了CdSe量子点与氧化石墨烯(GO)的复合材料.紫外-可见吸收光谱显示,CdSe量子点和CdSe/GO纳米复合材料的吸收边分别出现在583和556nm处.与纯CdSe量子点相比,GO层上的CdSe量子点的尺寸减小,由于量子限制效应,CdSe/GO纳米复合材料的光吸收波长在蓝移,从而拓宽了CdSe/GO纳米复合物的光吸收范围.PL光谱图显示CdSe量子点的可见光区的强宽发光峰出现在缺陷态的603 nm,而在576 nm处观察到CdSe/GO纳米复合材料的发射峰,峰位蓝移,光猝灭.GO表面上CdSe量子点的修饰改变了GO层间相互作用的范德华力和CdSe量子点与GO片相互作用的静电作用力.这些相互作用导致能级的变化,使得CdSe/GO纳米复合的发射峰蓝移.由于复合物中电子-空穴对的复合被抑制,CdSe/GO纳米复合材料的光致发光强度低于CdSe量子点,此对应于CdSe量子点到GO板的界面电荷转移.PL研究表明,GO修饰CdSe可促进电子-空穴对的分离.EIS测量方法进一步研究了CdSe量子点和CdSe/GO纳米复合材料的电荷输运行为.结果显示,加入GO后,CdSe量子点的阻抗值减小,表明GO的引入降低了电荷转移电阻,促进了其界面电荷转移.因此,CdSe/GO纳米复合材料具有较高的电荷分离效率,可以提高其光催化活性.拉曼光谱显示,由于CdSe量子点的激发,电子注入到GO中,使得CdSe/GO纳米复合物材料的拉曼光谱向更高的波数转移.通过BET性能测试,CdSe/GO纳米复合物的比表面积为10.4m2/g,比CdSe量子点的比表面积(5m2/g)增加了一倍.我们发现在太阳光的照射下,CdSe量子点和CdSe/GO纳米复合物对灿烂绿染料的光降解率分别为81.9%和95.5%,各自对应的光降解速率分别为0.0190和0.0345min-1.CdSe/GO纳米复合物增强的光催化性能归因于具有较大的比表面积以及氧化石墨烯的加入促进了电子-空穴对的有效分离.
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